A204656 Numbers n such that n!10+1 is prime.

0, 1, 2, 4, 6, 10, 16, 34, 46, 94, 146, 156, 166, 170, 194, 198, 206, 308, 456, 610, 614, 734, 1288, 1512, 1558, 2066, 2090, 2122, 3434, 3560, 3642, 3896, 4294, 4534, 4962, 5022, 5874, 8002, 9870, 11358, 11438, 13350, 15046, 16046, 20228, 25014, 30114, 35668, 38466, 46702, 48302

Offset: 1

Author

M. F. Hasler, Jan 17 2012

Keywords

• nonn
• hard

Comments

n!10 = product( n-10k, 0 <= k < n/10 ).

a(1)-a(51) proved prime by deterministic tests of PFGW. - Robert Price, Jun 08 2012

a(52) > 50,000. - Robert Price, Jun 08 2012

Links

• Ken Davis, Status of Search for Multifactorial Primes.
• Ken Davis, Results for n!10+1.
• Nathan Russell, n!10+2 results, primenumbers group, Jan 2012
• Nathan Russell, n!10+2 results, message 23995 in primenumbers Yahoo group, Jan 17, 2012.

Programs

PARI

for(n=0,9999,isprime(prod(i=1,(n-2)\10,n-(10*i),n)+1)& print1(n","))

Extensions

a(29)-a(51) from Robert Price, Jun 08 2012